The Library's Science, Technology and Business Division has published three additional subject bibliographies, each concerning flight, in its "Tracer Bullet" series. Not intended to be comprehensive, these compilations are designed—as the name of the series implies—to put the reader "on target."
Aerodynamics (Mechanics of Flight)
This bibliography provides references to a variety of materials in the collections of the Library that are useful in researching aerodynamics, the science that deals with the motion of air and other gases, or when gases move against or around solid bodies. Therefore, aerodynamics comes into play when air is flowing through ducts or other enclosed spaces such as wind tunnels, jet and rocket engines, and pipes.
Becoming familiar with the principles of aerodynamics allows us to understand why and how an aircraft can fly, as well as how to design better, more efficient aircraft. Aerodynamic principles may be used to find the best ways in which airplanes can get lift, reduce drag and remain stable by controlling the shape and size of the wing, the angle at which an aircraft is positioned with respect to the airstream and the flight speed.
Aircraft
This compilation refers the reader to sources that pertain to the history, present status and uses of aircraft. An aircraft is any machine or device capable of atmospheric flight. Aircraft can be classified as fixed-wing, rotary-wing, flapping-wing and lighter-than-air. The first three classes are heavier-than-air vehicles. Four forces act on a heavier-than-air vehicle in flight through the atmosphere: weight, aerodynamic lift, drag and thrust. Unlike a lighter-than-air vehicle such as a balloon or blimp, whose weight is balanced by an upward buoyancy force, a heavier-than-air aircraft must be propelled and maintained in the air. The scope of this guide is limited to heavier-than-air aircraft; the following Tracer Bullet refers to lighter-than-air aircraft.
Balloons and Airships
This Tracer Bullet focuses on balloons, airships, dirigibles, aerostats and blimps. A balloon is a vehicle whose flexible bag is inflated with a lighter-than-air gas, such as helium, so that it will rise and float in the atmosphere. Some sort of carrier for passengers can be attached to the bag. Only the altitude of free balloons can be controlled; their direction and speed depend on the wind. Airships, however, are equipped with some means of propelling and steering, so that controlled flight is possible. There are three types of airships: nonrigid, semirigid and rigid. Lighter-than-air vehicles get their lift from "aerostatic forces," rather than from aerodynamic forces that support a heavier-than-air aircraft. A balloon or airship's lift is derived from its buoyancy, which comes from the difference between the density of the atmosphere and that of the lifting gas that fills the aircraft.
These new publications are free and may be obtained by writing to the Science, Technology and Business Division, Library of Congress, Washington, DC 20540-4750, or by telephoning (202) 707-5664. A list is available of many other Tracer Bullets on timely subjects in science and technology.
For those with Internet access, all Tracer Bullets published from 1989 until several years ago, as well as selected older Tracer Bullets, can be accessed at memory.loc.gov/sctb. The three items announced here will be added to the database soon.